Fecal incontinence (FI), the involuntary leakage of feces, is a chronic problem with debilitating effects on health and well-being. Symptom management of FI is essential to maintain the dignity, self-esteem, and health of the individual, ease the burden of caregivers, and prevent admission to a nursing home. FI is worsened by loose/liquid stool consistency and the first step in its management is to firm stool consistency. The proposed study addresses a major gap in clinical management of FI since there is a lack of research on interventions to firm stool consistency in FI. The beneficial effects of fiber on stool consistency and FI appear to be related to the extent to which the fiber is fermented. A pivotal step in optimizing fiber therapy and improving the clinical response is to determine the importance of fermentation of fiber. The long-range objectives of this research are 1) to develop evidenced-based recommendations for using soluble dietary fiber to effectively manage FI and 2) to determine the mechanisms by which soluble dietary fiber improves stool consistency and FI. The objectives of this proposal are to determine the impact of fermentation on a fiber's ability to firm stool consistency, reduce FI, promote supplement tolerance, and improve quality of life in community-living adults with FI of loose or liquid stools. A randomized, controlled, single blind between groups design will be used. After a 2 wk. Baseline period, 184 community-living adults with FI of loose/liquid stool will be randomized to receive placebo or 16 g of total fiber/d in gum Arabic, psyllium, or carboxy-methylcellulose, representing three levels of ferment ability (completely, moderately, and non-fermentable, respectively). During the baseline and at the end of the supplementation period, subjects will complete a stool diary (14d), diet record (7d), FI Quality of Life survey, and collect all stools (7d). Differences among the measures of the groups after supplementation will be compared after controlling for baseline values of these measures using ANCOVA.